1. Field of the Invention
The process of the present invention relates to workover of a production hole to increase hydrocarbon production. More particularly, the process of the present invention relates to washing out formation sand within a production hole through the use of coil tubing, pressurizing a calculated quantity of spherical beads into the production zone and washing through the ceramic beads with a pre-packed system (screen) so that production is maintained through the media while holding back any sand within the formation.
2. General Background
In the overall process for drilling and production of hydrocarbons within the earth, at that point in the process where a hydrocarbon formation has been located at a particular depth, normally an exterior casing is lowered down the hole through the production zone, and an internal production tubing is lowered into the exterior casing. The annulus between the interior tubing and the exterior casing is packed off so that any of the hydrocarbons coming from the formation are recovered through the internal production tubing. Likewise, the exterior casing is packed off below the production zone so that the oil produced, of course, may go up to the surface. Following the packing off of the casing, the wall of the exterior casing is perforated through the use of a perforating gun or the like, so that the hydrocarbons may travel through the perforations in the wall of the casing and, under pressure, go to the surface for collection.
One of the problems which is confronted in this particular process is that as the formation is releasing hydrocarbons, a portion of the sand surrounding the exterior casing may collapse and the sand itself may be drawn into the well and collected on the surface. This, of course, is not beneficial, and must be dealt with so that the hydrocarbons are not contaminated with formation sand.
In the present state of the art, what is required is an extremely expensive undertaking which requires that a workover rig be set in place, and that the formation be "gravel packed", so that the formation is theoretically kept away from the casing, yet the hydrocarbons are allowed to seep through and be collected free of sand. However, the problem with gravel packing in this particular instance is that gravel, due to its irregular shape, may oftentimes cause a "bridging effect" within the casing, so that any washover tool or the like which is set within the gravel pack may become stuck within the hole, and the entire workover tool has to be retrieved in order to solve the problem. In addition, the "bridge" formed by the gravel pack may create voids beneath the bridge resulting in formation sand having direct contact with the hydrocarbons in the production tubing. In addition, oftentimes a workover rig, in order to clear production sand within the casing, runs to an expense of approximately $750,000 per job.
In addition, the use of gravel pack sand, in order to undertake a workover process due to its irregular shape will create fines in (a) transportation, (b) pumping through triplex pumps and (c) during the squeeze mode when the gravel is squeezed through the perforations. These fines could conceivably enter the screen and stick the internal wash pipe, which of course would have to be removed during the process under a great expense.
In the present state of the art, the three alternatives which the present invention could ultimately replace are (a) sand consolidation; (b) resin coated sand and (c) through tubing gravel packing. These three processes have met with limited success but cannot compare to the overall efficiency, low cost, and success of the present invention.
Therefore, there is a need in the industry for a process whereby the expense can be drastically cut in washing through a formation so that hydrocarbons may continue to be recovered from the ground without sand being mixed with hydrocarbons.